Sigma 18-35mm F1.8 Art DC HSM Lens for Canon F1.8 maximum aperture F16 minimum Ring-type ultrasonic-type AF motor with full-time manual focusing, 72mm filter size Minimum focusing distance 28 cm/ 11.0 in. USB Dock compatible, MC-11 compatible. Available in Canon EF (EF-S), Sony Alpha (dot), Nikon f (DX) mounts 0.23 optical Zoom